The development of user-friendly software for the calculation of effective patient dose from all diagnostic x-ray procedures is proposed. User input requiring only a few seconds will specify type of examination, phantom sex and size, beam energy and filtration, beam dimensions, beam angle, beam position on the phantom and source-to-patient distance. In addition to planar.radiography, this package will provide full capability of simulating x-ray CT and fluoroscopic procedures. There currently exists no methodology for rapid and customizable dose determination for all radiographic procedures. Calculations will be carried out via Monte Carlo simulation using a state-of-the-art transport code available in the public domain. Simulation times of only 5 minutes lead to statistical accuracies of < 5% for organs directly in the path of the bed Already available for this purpose is a sophisticated anthropomorphic phantom to which additions and refinements are proposed. The work scope for Phase I includes implementation of full CT and fluoroscopy capability, improvements to the phantom geometry and development of a user interface. The ultimate goal of this project will be to develop a dual commercialization track in which users have the option of purchasing software for on-site use or of accessing the software via the internet. PROPOSED COMMERCIAL APPLICATION: Once developed for operation under many operating systems, the software will be of potential use to all radiology departments in the country. Given its expected flexibility and ease of use it is reasonable to assume a significant fraction of these departments will purchase at least one copy. Other potential users include private radiological consultants and researchers.